I am guessing that you have Elements 3 and that you made a Custom Slideshow and set the WNV Output Quality to NTSC before you did the write of the slideshow to WMV file format on your hard drive.
Elements 3 itself can not write a Custom Slideshow Creation to a DVD disc; it can write in Video CD format to a CD disc. The Video CD format is lower resolution (and therefore lower quality) than the MPEG-2 NTSC format used on a DVD.
IF you have Adobe Premiere Elements installed, you will also see a menu choice of "DVD with Menu" on the menu of PSE 3 Creations.
The following Adobe techdoc talks about the interface from PS Elements 3 to Premiere Elements
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http://www.adobe.com/support/techdocs/330734.html>
As an alternative (if you do not have Premiere Elements), it is probably possible that you can save the Elements 3 WMV file to your hard drive, then use the burning software that came with your DVD burner to burn the DVD in NTSC format. However, this quality may not be as good as separate software that writes directly to a DVD in NTSC format.
I have noticed that several forum participants have ignored the Elements slideshow functions and used a separate slideshow program.
Barb O